When a male pushes his genetalia between his legs and then proceeds to bend over forward and turn around to display the image of his penis and testicles squashed between his legs, vaguely resembling an elephant's face.
In conjunction with the Elephant Face

If the male'ssex organs are not long/large/supple enough, the reverse elephant face has the possibility of turning into the 'traffic lights' or possibly even the 'division sign'.

*Male removes his trousers and underpants and proceeds to push his sex organs into a vice-like-grip between his legs, turns his body around so his backside is facing his friends*

He then proceeds to say 'Oi lads, check out my elephant face'. Meanwhile his friends make noises of horror whilst turning away/moving away from the offender/wretching. Laughter normally ensues after the reverse elephant face has been displayed.